Let me sum this one up...
I'll go through this in steps as there is too much to sum up in a couple of paragraphs, sorry if you think this is long winded.
Graphics - Are outstanding. The attention to detail is astounding sometimes I have been playing it and I have thought i was actually there fighting (i'm very impressionable and my imagination is wild) the walls, signs, faces everything is amazing.
AI - Very intelligent when fighting and always seems to help you out at exactly the right times. but very occasionally you will get the old situation of your team mates standing in a doorway and wont move but its nothing big.
Story - Is like a film. It's excellently executed BUT it is very similar to every other army game but I guess how many stories can they pull out of war? You know...President gets taken, executed on live tv and you have to go take out who is responsible.
The game modes are very entertaining because there is obviously the hide, shoot, move, throw grenade, realise your in the wrong place get shot, runaway missions but you get missions like being in one of those infra red carriers that shoot a mass of explosives at poor unsuspecting enemies, and the GREATEST sniper mission ever...Ever wondered what it would be like to be an actual sniper in the SAS and wear a ghillie suit (overalls with bits of tree attached to it) well this has it. (sorry im going on a bit now)
Multiplayer - Is fantastic but does get frustrating if you like games on normal difficulty. People on there are just too good! You can work your way up the rankings earning weapons and powerups by killing or completing challenges which gives the game more playability and more fun. Xbox live makes this online experience amazing. Just don't get shot too much!
Im not really too sure what else to write except this game is definately worth the money! even though it has been out for ages and by rights, should of been reduced by now...but the amount of hours you will spend unlocking everything and having a laugh...its worth every penny...If i lost my copy of the game I would definately buy it again even though most of the achievements have been unlocked...Oh yea!
Achievements! - A good array of achievements for novice to seasoned gamer...its fun trying to beat the record! ;) took me bloody ages!!!
Hope this has been helpful!